title: Age differences in biological monitoring of chemical exposure: a tentative description using a toxicokinetic model.
abstract: OBJECTIVE
  Specific factors responsible for interindividual variability should be identified and their contribution quantified to improve the usefulness of biological monitoring. Among others, age is an easily identifiable determinant, which could play an important impact on biological variability.
  
  
  METHODS
  A compartmental toxicokinetic model developed in previous studies for a series of metallic and organic compounds was applied to the description of age differences. Young male physiological and metabolic parameters, based on Reference Man information, were taken from preceding studies and were modified to take into account age based on available information about age differences.
  
  
  RESULTS
  Numerical simulation using the kinetic model with the modified parameters indicates in some cases important differences due to age. The expected changes are mostly of the order of 10-20%, but differences up to 50% were observed in some cases.
  
  
  CONCLUSIONS
  These differences appear to depend on the chemical and on the biological entity considered. Further work should be done to improve our estimates of these parameters, by considering for example uncertainty and variability in these parameters.
authors.affiliation: Institute for Work and Health, Lausanne University, Lausanne, Switzerland. Catherine.Tomicic@hospvd.ch
authors.forename: Tomicic
authors.initials: T
authors.lastname: Catherine
authors.forename: Droz
authors.initials: D
authors.lastname: Pierre-Olivier
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D003198:Computer Simulation; D004781:Environmental Exposure / Q000009:adverse effects*; D004784:Environmental Monitoring / Q000379:methods*; D006801:Humans; D008297:Male; D008875:Middle Aged; D008954:Models, Biological; D015262:Xenobiotics / Q000493:pharmacokinetics* / Q000633:toxicity*
chemical_list: D015262:Xenobiotics